(1) Field of the Invention
The present invention relates to a multiprocessor system, more particularly to a multiprocessor system which is used, for example, in a personal computer and the like, and in which different kinds of processors are freely switched and used without depending upon the architecture of each processor.
(2) Description of the Prior Art
In recent years, microprocessors have been developed and manufactured by various companies, and each of these microprocessors is used, for example, in a personal computer. There have also been developed various types of software for each of these processors. However, most of these types of software usually cannot be used interchangeably between the different processors, and, therefore, it is necessary to use special techniques to enable the use of the different types of software developed for the various processors by a single personal computer.
In order to make it possible for a single computer system, such as a personal computer, to utilize as many types of software as possible, there are conventionally known personal computers each of which comprises a plurality of different processors in one personal computer and these processors can be switched to enable the utilization of software developed for different processors. For example, in an FM-8 type personal computer manufactured by Fujitsu Limited, it is possible to switch between the 6809 type processor manufactured by Motorola Semiconductor Products and an optional type Z80 type manufactured by Zilog Corporation, thereby enabling the utilization of each of these processors. In an Apple II type personal computer manufactured by Apple Computer Inc., U.S.A., it is possible to switch between a 6502 type processor manufactured by Mostek Corporation and the optional type Z80 processor manufactured by Zilog Corporation, thereby enabling the utilization of each of these processors.
However, in the above-mentioned conventional computer systems, it is only possible to switch between particular predetermined processors when wishing to utilize a different processor. It is impossible to switch between processors which are not predetermined, and therefore, it is impossible to make the greatest possible use of the software developed for various processors. Moreover, in the aforementioned conventional systems, a main processor is permanently mounted on a main printed circuit board, and a printed circuit board containing another optional processor is connected to the main printed circuit board by a connector. Therefore, the type of the main processor is limited to that which can be used with a particular type of computer system, and thus it is impossible to use all types of processors as the main processor.